Browsing by Subject "Doppler"

Now showing 1 - 3 of 3
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    Association of second trimester uterine artery Doppler parameters with maternal hypertension 2-7 years after delivery
    (Elsevier, 2021-08-12) Miller, Eliza C.; Carper, Benjamin; Bello, Natalie A.; Merz, C. Noel Bairey; Greenland, Philip; Levine, Lisa D.; Haas, David M.; Grobman, William A.; McNeil, Rebecca B.; Chung, Judith H.; Jolley, Jennifer; Saade, George R.; Silver, Robert M.; Simhan, Hyagriv N.; Wapner, Ronald J.; Parker, Corette B.; NIH NICHD nuMoM2b and NHLBI nuMoM2b Heart Health Study Networks; Obstetrics and Gynecology, School of Medicine
    Background: Reduced uterine artery compliance is associated with adverse pregnancy outcomes (APOs) and may indicate underlying maternal cardiovascular pathology. We investigated associations between second trimester uterine artery Doppler (UAD) parameters and incident maternal hypertension 2-7 years after delivery. Methods: A cohort of 10,038 nulliparous US participants was recruited early in pregnancy. A subgroup of 3739, without baseline hypertension and with complete follow-up visits 2-7 years after delivery, were included in this analysis. We investigated UAD indicators of compliance including: 1) early diastolic notch; 2) resistance index (RI); and 3) pulsatility index (PI). We defined hypertension as systolic blood pressure ≥130 mmHg, diastolic ≥80 mmHg, or antihypertensive medication use. We calculated odds ratios (OR) and 95 % confidence intervals (95%CI) for associations between UAD parameters and hypertension, adjusting for age, obesity, race/ethnicity, insurance, smoking, and APOs. Results: A total of 187 (5 %) participants developed hypertension after the index pregnancy. Presence of early diastolic notch on UAD was not associated with incident hypertension. Increased RI and PI correlated with higher odds of hypertension (RI: adjusted OR 1.15 [95 % CI 1.03-1.30]; PI: adjusted OR 1.03 [95%CI 1.01-1.05] for each 0.1 unit increase). Maximum RI above 0.84 or maximum PI above 2.3 more than doubled the odds of incident hypertension (RI: adjusted OR 2.49, 95%CI 1.45-4.26; PI: adjusted OR 2.36, 95%CI 1.45-3.86). Conclusion: Higher resistance and pulsatility indices measured on second trimester UAD were associated with increased odds of incident hypertension 2-7 years later, and may be biomarkers of higher maternal cardiovascular risk.
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    Effect of Carbon Dioxide on the Twinkling Artifact in Ultrasound Imaging of Kidney Stones: A Pilot Study
    (Elsevier, 2017-05) Simon, Julianna C.; Wang, Yak-Nam; Cunitz, Bryan W.; Thiel, Jeffrey; Starr, Frank; Liu, Ziyue; Bailey, Michael R.; Biostatistics, School of Public Health
    Bone demineralization, dehydration and stasis put astronauts at increased risk of forming kidney stones in space. The color-Doppler ultrasound "twinkling artifact," which highlights kidney stones with color, can make stones readily detectable with ultrasound; however, our previous results suggest twinkling is caused by microbubbles on the stone surface which could be affected by the elevated levels of carbon dioxide found on space vehicles. Four pigs were implanted with kidney stones and imaged with ultrasound while the anesthetic carrier gas oscillated between oxygen and air containing 0.8% carbon dioxide. On exposure of the pigs to 0.8% carbon dioxide, twinkling was significantly reduced after 9-25 min and recovered when the carrier gas returned to oxygen. These trends repeated when pigs were again exposed to 0.8% carbon dioxide followed by oxygen. The reduction of twinkling caused by exposure to elevated carbon dioxide may make kidney stone detection with twinkling difficult in current space vehicles.
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    In Vitro Ultrasound Measurements of Powered and Unpowered Total Cavopulmonary Connection
    (Austin Publishing Group, 2014) Iliff, BP; Kerlo, AEM; Chen, J; Rodefeld, MD; Goergen, CJ; Department of Surgery, IU School of Medicine
    Three-staged Fontan palliation is performed on children suffering from single ventricle congenital heart disease. The series of surgical procedures reroutes blood from the vena cavae directly to the pulmonary arteries, creating a total cavopulmonary connection (TCPC). A viscous impeller pump (VIP) is currently being developed as a cavopulmonary assist device that can modestly augment cavopulmonary flow, reduce systemic venous pressure, and improve ventricular preload. This study used ultrasound to visualize complex flow patterns in powered and unpowered in vitro mock Fontan circulations. The idealized TCPC was modeled with a silicone mold and blood analog made of water and glycerol that was seeded with 10-μm glass beads. B-mode, color Doppler, and pulsed-wave Doppler images were used to visualize complex flow patterns in the idealized TCPC with (1) no VIP, (2) static VIP, and powered VIP rotation rates of (3) 500 and (4) 2,000 rotations per minute (RPM). Pulsed-wave Doppler data showed higher mean velocities and greater variance in the outlets relative to the larger inlets. The maximum inlet velocity ± SD increased from 10.9 ± 3.53 cm/s with no VIP to 15.9 ± 1.03 when the VIP was rotating at 2,000 RPM. Likewise, the maximum outlet velocity increased from 14.9 ± 11.2 cm/s to 18.9 ± 7.25 cm/s at 2,000 RPM. The faster mean velocities with the VIP rotating suggest that the pump augments cavopulmonary flow. The results of this study suggest that measuring complex flow patterns with ultrasound in vivo could be used clinically to optimize VIP positioning and rotation rate during and after implantation.